1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
|
left <- function(x, n=6L, ...) UseMethod("left")
right <- function(x, n=6L, ...) UseMethod("right")
.leftright <- function(x, n=6L, add.col.nums = TRUE,
direction = c("left", "right"), ...)
{
stopifnot(length(n) == 1L)
ncx <- ncol(x)
if (add.col.nums && is.null(colnames(x)))
colnames(x) <- paste0("[", 1:ncx, ",]")
if (n < 0L)
n <- max(ncx + n, 0L)
else
n <- min(n, ncx)
if (direction == "left")
sel <- seq.int(from=1, length.out = n)
else # direction="right"
sel <- seq.int(to = ncx, length.out = n)
x[, sel, drop = FALSE]
}
left.data.frame <- function(x, n=6L, add.col.nums=TRUE, ...)
.leftright(x, n=n, add.col.nums=add.col.nums, direction="left")
right.data.frame <- function(x, n=6L, add.col.nums=TRUE, ...)
.leftright(x, n=n, add.col.nums=add.col.nums, direction="right")
left.matrix <- left.data.frame
right.matrix <- right.data.frame
|
